Introduction: Coffee is one of the most widely consumed beverages by the people all around the world. This study was aimed to evaluate the effect of sugar addition, double effects of sugar addition and roasting degree on the polyphenol content, and antioxidant activity of Turkish-style coffee brews. Materials and Methods: The levels of three phenolic compounds (chlorogenic acid, caffeic acid, sinapic acid) and caffeine by reversed-phase high performance liquid chromatography (HPLC) method, as well as chromaticity parameters, absorbance value at 420 nm, total phenolic and flavonoid content, antioxidant activities with two methods (DPPH and FRAP methods) were determined in different degree of roast Turkish-style coffee brews with sugar and without sugar. Results: It was found that antioxidant activity of Turkish-style coffee brews was increased while the phenolic content was decreased due to the degree of roasting process. Also, the addition of sugar into Turkish-style coffee brews at cooking stage caused decrease both in antioxidant activity and polyphenol content. Conclusion: The study indicated that light roasted coffee brews showed greater polyphenol content and medium roasted coffee brews had greater antioxidant capacity compared to other samples. Consumption of coffee brews without sugar provided the higher health benefits.